This invention relates to admitting air into a flexible inflation of a teat cup assembly of a milking machine.
The teat cup of a double action milking machine has a rigid shell with a resilient liner which receives the teat. A constant vacuum is applied at the end of the teat through the stem of the teat cup, permitting milk to flow to a milk receiver. A pulsating vacuum is applied to the inflation chamber between the liner and the shell 40 to 60 times per minute, causing expansion and contraction of the resilient liner. When the resilient liner is expanded around the teat (i.e. the chamber between the cup and the shell is evacuated), milk flows from the teat. The milk must be removed from the liner through its stem and into the attached milk hose at a speed sufficient to prevent interference with expansion and contraction of the liner.
Noorlander U.S. Pat. No. 3,476,085 provides an air inlet plug in the wall of the stem of the teat cup near its upper end. The plug has an opening therethrough for admitting a metered amount of atmospheric air into the upper end of the stem. The Noorlander air inlet is subject to blockage, as by dried milk, flies, straw or the like.